Short and slight, with an off-kilter smile and wide anime eyes, Shannan Gilbert had drifted into escort work when she was about 20 as a way to earn money while trying to make it as a singer. That night at Oak Beach, she was wearing a blonde wig, a pair of dangly hoop earrings, a brown leather jacket, and jeans. On nights like this, she’d tell her boyfriend she was going out on auditions.

The oldest of Mari Gilbert’s four daughters, Shannan finished high school in New Paltz at age 16. “She wasn’t street-smart, but she was book-smart,” Mari says. Shannan had been diagnosed with bipolar disorder but stopped taking her medication, complaining that it gave her the shakes. After graduating, she worked at a hotel, an Applebee’s, and a senior center, but by 2007, she had moved to New Jersey with a boyfriend and signed on with an escort agency. She had at least one arrest in her record, having been rounded up with some other girls from Upper Saddle River, and one time was beaten to the point where she needed a titanium plate in her jaw. Two years ago, she started posting ads for herself on Craigs­list, where she could charge $200 an hour and keep two thirds of the fee; the other third went to a driver, who would take her to dates and provide security. Shannan liked to party—mostly pot, coke, and prescription drugs—but if she managed to make it through the night without burning through too much of what she earned, she could get home after five calls with $600 or more in her pocket.

The extra money had allowed Shannan to move into a place of her own for the first time, in Jersey City, and she was close to completing a series of online college classes that might have helped her stop escorting. But she liked to visit her family, take her sisters on shopping sprees, and lavish gifts on her nieces and nephews. Mari, who works at a Wal-Mart, knew where the money was coming from and searched for a way to talk about it with her daughter. “I tried to tell her ‘Don’t do it. Stop. Move back in with me,’” Mari says. But Shannan refused. “Mom,” she would say, “I hardly have to do nothing, and I get thousands of dollars.”

On May 1, 2010, at about 2 a.m., Shannan arrived in a dark SUV at a two-story wood-frame house on Fairway Drive in Oak Beach, Long Island, a quiet gated community a few miles from Fire Island, on the string of barrier islands along South Oyster Bay. The house belonged to Joseph Brewer, a 46-year-old unemployed ­financial adviser who was separating from his wife. A few hours earlier, Brewer had responded to an ad Shannan had posted on Craigs­list. The most thorough account of what happened next comes from Michael Pak, a driver Shannan had worked with before and was working with that night. Once Pak dropped off Shannan at Brewer’s house, he says, he waited in the SUV, playing poker on his cell phone, while Shannan and Brewer were together. Another source reportedly saw the two leave the house once, in Brewer’s car, for about fifteen minutes. It’s not clear where they might have been going, although Pak says it wouldn’t have been unusual if Shannan were looking for drugs. At about 5 a.m., Pak says, Brewer came out of the house and asked him for help.

Inside, Pak says, he found Shannan in a panic, clutching her cell phone. Police records would later show that Shannan had called 911 from that phone at 4:51 a.m. and kept the dispatcher on the line for 23 minutes. On the 911 recording, she sounds frantic; voices in the background can be heard trying to calm her down (if the police know who they are, they aren’t saying). Shannan never told the 911 dispatcher where she was—it’s possible she didn’t know, having been driven there—so the police had no way of sending help. Pak says he tried to get Shannan to leave with him, but she refused to go. She seemed delirious; he thought it might be drugs. Pak left the house, frustrated. He got back into the SUV and waited.

A minute or two later, Pak says, Shannan bolted from the house, stumbled down the front steps, and took off down the road. Pak says he followed her in the SUV, but she kept running, screaming for help. A neighbor, 75-year-old Gustav Coletti, was up early, shaving, when he heard a pounding at his door. When he opened it, he says, Shannan ran inside, shrieking that her life was in danger. Coletti says he told Shannan he’d call the police. But for reasons that remain unclear—had someone threatened to harm her if she called the cops? Was she afraid she’d get arrested?—­Shannan begged Coletti not to make the call.